It's the analytical technique that has been successfully used to study Martian terrain for almost ten years… and it's about to be deployed a little closer to home. RUTH DAWKINS reports
Using laser analysis data for mineral mapping
Laser Induced Breakdown Spectroscopy (LIBS) is a rapid chemical analysis tool that is used to detect and characterise materials.
By focusing a powerful laser pulse onto the surface of solid, liquid or even gaseous matter, and then analysing the emission spectra from the resulting microplasma, it becomes possible to determine the elemental composition of the sample.
CSIRO, in partnership with Australian gold producer Northern Star Resources, is embarking on an exciting new project that will utilise LIBS technology to analyse core samples from mining sites, before developing highly detailed, accurate mineral maps with the resulting data.
Portable technology used on Mars brought down to earth
LIBS has a number of significant advantages over other mineral mapping tools such as Scanning Electron Microscopes (SEM).
As evidenced by its use on Mars, it's a robust and portable technology, suitable for use in the field.
Crucially though, it's also a much faster technique: an analysis that would take 1.5 hours using SEM might take just five minutes using LIBS.
One key difference between the two approaches is that unlike SEM, LIBS doesn't require any pre-treatment of samples.
Instead, the analysis can take place in situ without any polishing required. Removing the need for transportation, labour and laboratory costs means the technology has the potential to provide significant economic savings to mining companies.
In-situ analysis for rapid decision making
According to CSIRO's Dr Adam Bath, a research scientist specialising in hydrothermal footprints, that ability to process samples more rapidly means that LIBS could revolutionise Australia's mining industry.
"Until recently there has been something of a disconnect between mineral system research and mineral exploration because the required technology simply hasn’t been there," said Dr Bath.
"With previous approaches to mineral mapping, where we've needed to collect samples and take them back to the laboratory for processing, it has sometimes taken as much as 6 or 12 months for the resulting information to flow back to the company."
"But if we can get to the stage where we have instruments on site providing real time data, that will lead to much faster and more efficient decision making."
Piloting technology with Northern Star Resources
The initial project with Northern Star is due to last for one year, with the aim of getting the LIBS instrument operating at a level where it can be used effectively on Australian mining sites.
According to Dr Bath, the hardware itself is already fit for purpose, but there is still some work to be done refining the software, building up mineral libraries, and ensuring that the enormous datasets are being processed as quickly and efficiently as possible.
If that work is successful, then Dr Bath believes it will lead to a fundamental shift in the role of geologists working with mining companies.
"If we can accelerate the in-situ analysis of rocks for quantified mineralogy, then that frees up geologists to focus on geology," Dr Bath says.
"Rather than processing and recording measurements, they're able to engage in more critical thinking about the minerals and alteration patterns."
"Real time data opens up conversations about where to sample, how much to sample, and allows you to take a different approach based on what you're seeing at that particular moment."
A further benefit of the LIBS approach is that it will lead to much more consistent analysis, meaning that the resulting data can be used with confidence by the industry.
"There are a lot of very good industry geologists," says Jamie Rogers, Northern Star’s General Manager for Exploration.
"But the subjective nature of the work leads to inconsistencies."
"Mapping alteration patterns, especially in gold systems, can be very complex."
"You can't always physically differentiate subtle changes in mineral species, so having the ability to do an accurate analysis of a sample very quickly and then use that information to map alteration mineralogy in three dimensions will be hugely valuable."
The LIBS project isn’t the first collaboration between CSIRO and Northern Star, but Jamie Rogers believes the work is a natural follow-on from previous initiatives.
"We've been working on mapping mineral systems with CSIRO for many years already, using lab-based tools like SEM and TIMA," he says.
"But for all this time we have been waiting for a practical tool that can be used in a high-production mine environment."
"Dr Bath deserves a lot of credit for his drive to expand the use of LIBS beyond the manufacturing sector and into mining and minerals."
From the lab to real-world solutions
It’s clear that despite his role as a fundamental geochemist, Dr Bath believes strongly in taking research science out of the laboratory and putting it into the hands of industry where it can be put to good use.
"I definitely think this application of LIBS has the potential to be disruptive technology," Dr Bath says.
"Key to that is the ease of use. Analysing a core sample with LIBS is like putting a cup in a microwave."
"The instrument itself can be operated by a fieldhand, and it can be working pretty much round the clock."
"The exciting part is when we see the resulting data in the hands of the mining industry so they can make their exploration activities as efficient as possible."